从多个表更新查询，以获取特定ID和联接限制1

Question

我有两个表，我想每天从torrents中更新scrapes中的行。

擦伤：

id, torrent_id, name, status, complete, incomplete, downloaded
1, 1, http://tracker1.com, 1, 542, 23, 542
2, 1, http://tracker2.com, 1, 542, 23, 542
3, 2, http://tracker1.com, 1, 123, 34, 43
4, 2, http://tracker2.com, 1, 123, 34, 43
5, 3, http://tracker1.com, 1, 542, 23, 542
6, 3, http://tracker2.com, 1, 542, 23, 542
7, 4, http://tracker1.com, 1, 123, 34, 43
8, 4, http://tracker2.com, 1, 123, 34, 43
9, 5, http://tracker1.com, 1, 542, 23, 542
10, 5, http://tracker2.com, 1, 542, 23, 542
11, 6, http://tracker1.com, 1, 123, 34, 43
12, 6, http://tracker2.com, 1, 123, 34, 43

torrents:

id, name, complete, incomplete, downloaded
1, CentOS, 0, 0, 0
2, Ubuntu, 0, 0, 0
3, Debian, 0, 0, 0
4, Redhat, 0, 0, 0
5, Fedora, 0, 0, 0
6, Gentoo, 0, 0, 0

scrapes可能有多个name，但是我只想从第一个找到的值(为了更好的性能)获取值，而且我只需要在一个查询上更新torrents ids 1, 3, 6。

Answer 1

UPDATE (SELECT * FROM scrapes WHERE torrent_id IN(1,3,6) GROUP BY torrent_id) as `myview` JOIN torrents ON myview.torrent_id=torrents.id SET torrent.complete=myview.complete WHERE 1